Quality Assurance & Improvement Flashcards

Which Docker command runs a container's built-in health check immediately and returns the result without waiting for the interval?

Answer: There is no way to trigger a health check on demand

Docker does not provide a direct command to trigger a HEALTHCHECK on demand; you must exec into the container and run the check command manually.

A Dockerfile HEALTHCHECK reports 'unhealthy' but the container keeps running. What is the default Docker behavior in this situation?

Answer: The container continues running; orchestrators like Swarm may reschedule it

Docker itself does not stop an unhealthy standalone container; it is up to orchestrators (Swarm, Kubernetes) to act on the unhealthy status.

When using 'docker build --no-cache', what quality assurance benefit does this provide?

Answer: It ensures every layer is rebuilt fresh, catching dependency drift

Building without cache forces all layers to be re-executed, ensuring the image reflects the latest upstream dependencies and revealing any drift.

Which tool is specifically designed to scan Docker images for OS and library CVEs and integrates natively with Docker Hub?

Answer: Docker Scout

Docker Scout is Docker's native vulnerability scanning and supply-chain security tool that integrates directly with Docker Hub and Docker Desktop.

A developer wants to enforce that no container in a Swarm service runs as root. Which mechanism enforces this at the orchestration level?

Answer: Docker Swarm --user flag on service create

The '--user' flag on 'docker service create' overrides the image default and ensures all tasks in the service run as the specified non-root user.

What does the '--iidfile' flag in 'docker build' help with in a CI/CD quality pipeline?

Answer: It saves the image ID to a file so downstream pipeline steps can reference the exact built image

'--iidfile' writes the resulting image ID to a file, allowing subsequent CI steps to reference the precise image digest rather than a mutable tag.

Which 'docker service update' flag triggers a rolling update while ensuring a minimum number of tasks remain healthy before proceeding?

Answer: --update-max-failure-ratio

'--update-max-failure-ratio' sets the fraction of tasks that may fail before the rolling update is considered failed and halted or rolled back.